Ubiquitin-like protein ISG15 (ISG15) is a 165-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P05161.
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The mean pLDDT of this model is 85.9 (confident overall). pLDDT is AlphaFold's per-residue confidence score from 0 to 100. In MolViewer, choose the B-factor color scheme to color the model by pLDDT, because AlphaFold stores it in the B-factor column.
| pLDDT band | Meaning | Share of residues |
|---|---|---|
| Above 90 | Very high: backbone and side chains are usually accurate | 42% |
| 70 to 90 | Confident: backbone generally right | 50% |
| 50 to 70 | Low: treat with caution | 4% |
| Below 50 | Very low: often disordered regions | 4% |
What pLDDT means and how to read it
Ubiquitin-like protein which plays a key role in the innate immune response to viral infection either via its conjugation to a target protein (ISGylation) or via its action as a free or unconjugated protein (PubMed:27564865, PubMed:39465252). ISGylation involves a cascade of enzymatic reactions involving E1, E2, and E3 enzymes which catalyze the conjugation of ISG15 to a lysine residue in the target protein (PubMed:33727702). Its target proteins include IFIT1, MX1/MxA, PPM1B, UBE2L6, UBA7, CHMP5, CHMP2A, CHMP4B and CHMP6. Isgylation of the viral sensor IFIH1/MDA5 promotes IFIH1/MDA5 oligomerization and triggers activation of innate immunity against a range of viruses, including…
Homodimer; disulfide-linked (PubMed:2440890). Interacts with, and is conjugated to its targets by UBE1L (E1 enzyme) and UBE2E2 (E2 enzyme) (PubMed:11157743, PubMed:15131269). Interacts with NEDD4 (PubMed:18305167). Interacts with PARP12; this interaction inhibits PINK1/Parkin-dependent mitophagy (PubMed:39465252)
Cytoplasm, Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 6FFA | X-ray | 1.5 Å | B=79-155 |
| 3PHX | X-ray | 1.6 Å | B=79-156 |
| 3RT3 | X-ray | 2.01 Å | B=1-158 |
| 7S6P | X-ray | 2.15 Å | A/B/C/D/E/F=2-157 |
| 3SDL | X-ray | 2.29 Å | C/D=1-157 |
| 3PSE | X-ray | 2.3 Å | B=1-156 |
| 3R66 | X-ray | 2.3 Å | C/D=1-157 |
| 5W8U | X-ray | 2.41 Å | B/D=80-156 |
| 1Z2M | X-ray | 2.5 Å | A=1-155 |
| 9NN9 | X-ray | 2.59 Å | A/C/E=1-157 |
| 5TL6 | X-ray | 2.62 Å | A/C=80-157 |
| 5W8T | X-ray | 2.76 Å | B/D=80-156 |
| 6XA9 | X-ray | 2.9 Å | B/D/F=79-157 |
| 7RBS | X-ray | 2.98 Å | B/D/F/H/J=2-157 |
| 6BI8 | X-ray | 3.0 Å | C/D=1-156 |
| 8SE9 | EM | 3.2 Å | B/D=1-157 |
| 8SEB | EM | 3.24 Å | B=1-157 |
| 8SV8 | EM | 3.38 Å | B/D=1-157 |
| 8SEA | EM | 3.4 Å | B/D=1-157 |
| 8OIF | EM | 3.5 Å | I=1-157 |
Showing 20 of 21 experimental structures (best resolution first).
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